A new kind of toilet using bacteria to break down human excreta has been deployed in Indian trains over four years to 2017, at a cost of Rs 1,305 crore, but this toilet is no better than a septic tank, the Indian Institute of Technology, Madras, has concluded after a two-year long study.

As many as 93,537 “bio-digesters”--as the toilets are called--have been installed in mainline express and mail trains by the Indian Railways. These are small-scale sewage-treatment systems beneath the toilet seat: Bacteria in a compost chamber digest human excreta, leaving behind water and methane. Only the water, disinfected later, is let out on the tracks.

That is how it is supposed to work.

However, sanitation experts and various studies--including commissioned by the railways--have pointed out that most of the new “bio-toilets” on Indian trains are ineffective or ill maintained and the water discharged no better than raw sewage.

“Our tests have found that the organic matter (human waste) collecting in the bio-digesters do not undergo any kind of treatment,” IIT professor Ligy Philip, who headed the latest study, told IndiaSpend. “Like in the septic tanks, these bio-digesters accumulate slush (human excreta mixed with water).”

The IIT study on bio-toilets, shared exclusively with IndiaSpend, was sponsored by the Bill and Melinda Gates Foundation and submitted last week to the union ministry of urban affairs.

Despite the criticism, an additional 120,000 coaches are to be fitted with these bio-toilets, jointly developed by the Defence Research and Development Organisation (DRDO) and the Indian Railways, by December 2018. This is likely to cost Rs 1,200 crore, the railways revealed on November 2, 2017, in response to a Right to Information (RTI) request.

A bio-toilet tank fitted beneath a north-western railways coach.

The bio-digester project in the Indian Railways began during the previous United Progressive Alliance (UPA) regime. But the project has been speeded up under Prime Minister Narendra Modi’s Swachh Bharat (Clean India) campaign. The idea is to meet this target in time for the celebration of Mahatma Gandhi’s 150th birth anniversary in 2019, said railway ministry spokesperson Anil Kumar Saxena. The Swachh Bharat campaign has been dedicated by PM Modi to Gandhi.

Indian Railways are often described as the world’s biggest toilet: It ejects around 3,980 tonnes of faecal matter--the equivalent of 497 truck-loads (at 8 tonnes per truck)--onto rail tracks every day, according to a report released by the Comptroller and Auditor General (CAG) in 2013.

The network has 9,000 passenger trains with 52,000 coaches with toilets that discharge human waste on to rail tracks. Covering 65,500 km across the country, these trains transport 24 million passengers every day, the equivalent of the population of Australia.

Since 1993, the Indian Railways have been experimenting with a host of technologies used worldwide to replace the open discharge system. This included vacuum toilets based on suction, commonly seen in aircraft; “controlled-discharge” toilet systems (CDTS) which allow waste to be dropped only after a train acquires a speed of 30 kmph, thus keeping stations clean; and “zero-discharge” toilets, in which solid waste is stored, evacuated and then dumped in pits for composting and the liquid filtered for recycling.

In 2008, the railways decided to install the bio-digester model developed by the Gwalior-based Defence Research and Development Establishment (DRDE).

Responding to the criticism of the bio-toilet, government officials said that the flaws are being fixed. “The issues regarding the bio-digesters are of a minor nature and are being effectively addressed. Some changes (in design or execution strategies) are inevitable, as this is a continuous process,” said Saxena, the railway ministry spokesman.

Currently, there are nine units manufacturing these bio-toilets.

Questions raised about bacteria used in green toilets

Lokendra Singh, former director of the DRDE, had, after an expedition to Antarctica, brought home psychrophilic bacteria that can survive in extremely low temperatures. The bacteria were mixed with cow dung and normal soil, which have methogens (microorganisms that produce methane) capable of breaking down human excreta. This was then supplied to the manufacturers of rail bio-digesters.

“Because of the presence of a compound of bacteria, the bio-degradation process is set off in the toilet chambers--the bacteria eat up the organic matter (human excreta) and produce methane gas and water as byproducts,” Singh said.

The Indian Railways have also been toying with the idea of setting up two factories to mass produce this bacterium.

But Singh’s claims of a scientific breakthrough using the bacteria from Antarctica have been questioned on the following grounds:

  • The bacterium, Singh admitted, has not obtained an independent or a third-party certification from an organisation such as the UIC (Federation of European Railways);
  • The DRDO does not have a patent for the design or manufacture of these bio-toilets. A patent is necessary to market a commercial product. DRDO only has a patent for the design of “railway toilet tank”, as the organisation’s website reveals;
  • The railways do not maintain centralised data on the functioning of bio-digesters on parameters of effluent analysis, their charging or emptying locations;
  • These bio-toilets do not eliminate the problem entirely: Once the tank is filled, human excreta is allowed to drop down onto the tracks.

Three experts had flagged problems with bio-toilets

This is not the first time the railways’ bio toilet project has been criticised. A 2009 study jointly conducted by the Lucknow-based Research Designs and Standards Organisation (RDSO) and IIT Kanpur concluded that no treatment of human excreta was happening in the bio-digesters installed in railway toilets.

“We had found the discharge from these toilets as being no different from raw sewage,” said IIT professor Vinod Tare, who had headed the study, which the railway ministry has not made public.

On September 14, 2004, DRDO scientist Y Ashok Babu sent a letter to the then chief vigilance commissioner Pradeep Kumar, terming the bio toilets “farce (sic) technology”.

Sulabh International founder Bindeshwar Pathak--who had earlier been named the brand ambassador of the railways’ cleanliness mission--has also expressed serious reservations about the effectiveness of the “Antarctica bacteria” at a meeting with railway board officials in January 2016.

“I had recommended the use of removable steel tanks in train toilets and the installation of biogas digesters at the junctions,” Pathak said.

The bio-toilets had “more than 100% chance of getting choked”, said M Raghaviah, general secretary of the National Federation of Indian Railways, in an August 2015 letter sent to the Railway Board. “The carriage and wagons staff is routinely facing the inconvenience of cleaning up the choked tanks,” he said.

The DRDO bio-digesters were first installed at Siachen glacier in 2000 and subsequently at the 2013 Kumbh Mela, the massive Hindu festival that marks a solar eclipse, in Allahabad. Recent news reports (such as this report in the New Indian Express) have pointed out that bio-toilets are malfunctioning in trains.

Singh rejected these allegations. “Frustrated scientists who have never worked on the project are raising such issues,” he said. “Of course, there are some problems but these are being addressed by the railways. Bio-digester manufacturers do not have previous experience. So, some problems are emerging but issues will shortly get sorted out.”

Singh, who has assumed charge as the chairman of the Digesters and Bio-Toilet Manufacturers Association (DBMA) after his retirement from DRDE this year, said questions of “conflict of interest” did not apply in his case, as he held only an “honorary position with the DBMA”.

Incumbent DRDE director DK Dubey refused to comment in the matter and a questionnaire emailed to him remained unanswered until the time of writing. DV Kamboj, project in-charge at DRDE, said he was not authorised to speak to the media.

Bio-toilets are often choked, broken or malfunctioning

Documents available with IndiaSpend suggest that there are serious issues with the bio-toilet venture. At a high-level meeting convened by the railway board on October 26, 2017, with functionaries from 17 zones, the following concerns were emphasised:

  • Bio-digester toilets were giving off an overpowering stench on account of the improper functioning of mechanical peripherals fitted in them;
  • Toilets were getting jammed often, not only because passengers were tossing bottles, cigarette butts, gutka (chewable tobacco mix) packets and soiled sanitary napkins into them but also because mechanical fixtures such as valves were non-functional;
  • Water pressure available for flushing in these toilets was inadequate (bio-digesters need 5 litres of water per flush);
  • Mounting and securing apparatus of the toilet tanks were faulty, leading to regular breakage of rubber connector and safety wires.

An internal review of bio digesters conducted for September 2017 on five divisions of the Northern Railway Zone indicated 10% failures on account of internal choking in the Delhi division of Northern Railways; 15.7% cases of clutch wire failures and 19.4% failures of lab samples testing.

Cost of manufacture, fitment has climbed from Rs 52,000 to over Rs 75,000

During the last three years of the second UPA government (2011-14), 9,350 bio-toilets were fitted in trains but the figure rose by 539%, to 59,735, in the first three years of the NDA government (2014-17).

In the current financial year (2017-18), 24,215 bio-toilets had been fitted until August 30, bringing the cumulative figure to 93,537, the railways said in the RTI reply of November 2, 2017.

In this period, the cost of manufacture and fitment of bio-toilets climbed from an average of Rs 52,000 per unit to over Rs 75,000 per unit. After the imposition of the Goods and Services Tax (GST), this cost burden has spiked further, with the railways having to absorb the 18% levy.

“Cost escalation is inevitable, as manufacturing costs have been rising,” said Manoj Jha of Faridabad-based Arkin Technologies that manufactures and supplies bio-digesters to the railways.

In response to an RTI appeal from Dehradun-based activist Prabhu Dandriyal, the railways stated that the Hubli workshop of South Western Railways had been supplied 2,152 toilets at a cost of over Rs 22 crore during the financial year 2016-17. Based on this calculation, the current cost being borne by the railways works out to more than Rs 100,000 per unit.

By the time the task is completed, the railways are likely to exceed their budget of Rs 1,200 crore for additional bio-toilets. Arvind Dethe, a bio-toilet manufacturer based in Akola in Maharashtra, has been selling a similar toilet at Rs 6,000.

“Everybody engaged with the plan is aware that the current bio-digester plan is unlikely to achieve the goal of providing an environment-friendly and sustainable solution,” a railway official said, requesting anonymity because he is not authorised to speak to the media. “But officials are keeping quiet on account of pressure from the political leadership to fulfill the targets.”

As many as 95% of the bio-toilets fitted so far were faulty, claimed another official posted in the carriage and wagon department who did not wish to be named. His department is responsible for the maintenance of toilets.

DRDO scientist Ashok Babu, in his email of May 21, 2016, to then defence minister Manohar Parrikar, rubbished official claims about the bio-toilets, alleging that these were nothing but “gobar gas plants”.

“With basic training, a village mason can build such toilets,” he alleged. “The plan is being pushed by a nexus of officials and vendors.”

The railways have spent Rs 22 lakh on the repair of “faulty” bio-toilets in the Southern Railway zone alone, according to an October 10, 2017, RTI reply to Dandriyal, the Dehradun-based activist.

“Funds are not so much a constraint; but a bigger problem is that--on account of the business interests of the railways to run more and more trains--it becomes difficult to spare coaches for repair work,” said a railway ministry official who did not wish to be named. “Coaches with faulty toilets need to be marked ‘sick’ and moved to the nearest of the 29 workshops of the Indian Railways for repair. But the time and luxury for such things is not easily available with the Indian Railways.”

Railways now looking at vacuum toilets

Confronting “irresolvable issues” on the non-functioning of the DRDO toilets, the Indian Railways have begun exploring other options including the procurement of the vacuum toilets commonly used in aircraft or trains in western countries.

The Chennai-based Integral Coach Factory (ICF) has already floated a global tender to acquire vacuum toilets. “To begin with, these will be fitted in premier trains including the Rajdhani, Shatabdi and the Durontos,” a ministry official said.

Singh said that the idea was to develop “hybrid toilets” by fitting vacuum toilets atop the bio-digesters already installed. “Subsequently, lavatories will mainly have vacuum toilets, with just one big bio-digester installed in half portion of the guard’s cabin at the end of the train,” the official said.

This policy U-turn means not only that has time and money invested in the bio-digesters has been wasted but also that the railways will now need to pump in more funds to execute its green toilets plan

IndiaSpend Solutions

  • “IIT Kanpur developed 'zero-discharge toilets' which have a separator to segregate the solid matter of human excreta from the liquid portion. The liquid portion, after treatment, can be used for flushing, while the solid waste can be evacuated at junctions with the aid of assembly suction pumps. Human excreta--mixed with cow dung--could subsequently be used for vermi-composting. The toilet model developed by us would have cost much less, but for some reason, the Railways dropped the idea.”--Vinod Tare, professor, environmental and engineering management programme, IIT Kanpur
  • "We had suggested that removable steel tanks be fitted beneath train toilets. The waste matter collected in these tanks could be sucked into bio-gas plants that could be set up at major stations. Electricity generated from these plants could be used for station lighting, water heating or even cooking purposes."--Bindeshwar Pathak, founder, Sulabh International
  • “R&D efforts are needed to solidify the bacteria that are being added to the bio-digesters in the liquid form. In a liquid form, these are ineffective. The private sector--as also the non-government organisations--needs to be provided incentives and resources to conduct R&D work. At present, there is over-dependence on DRDO as the technology provider. This is not a happy situation to be in."--Abhay Khanna, President, Suvidha Foundation
  • "Attach 'exclusive toilet trains' to passenger coaches. Waste collecting in the toilet tanks can be mechanically pulled down into the underground drainage systems at designated stations."--Anwar Hussain Shaik, bureaucrat

(Jha is a New Delhi-based freelance journalist.)


The railways ministry has responded to our story ‘New Toilets In Indian Trains No Better Than Septic Tanks: IIT Study’ published on November 23, 2017, pointing out what it calls “factual inaccuracies” and a lack of “technological understanding”. We are carrying the various points raised in the rejoinder verbatim, along with responses from the reporter, Srinand Jha.

Railways Ministry: “As per email from Professor Ligy of IIT, Madras, they have not conducted any study on the bio-toilets installed in Railways coaches. They had conducted study on stationary toilets on selected 15 field installed units and 6 units installed at IIT Madras Campus with bio-digesters based on DRDO technology. Thus, it is clear that the article is misleading as it is not based on study on toilets of Railway coaches.”

Srinand Jha: In my conversation with Ligy Philip on November 15, she said the findings of her study were valid for all types of DRDO-designed bio-digesters, including those installed in trains. “There is absolutely no difference. The same technology and the same bacteria is being used for both the land-based and the train bio-digesters,” she said. Subject experts such as Vinod Tare of IIT Kanpur, Bindeshwar Pathak of Sulabh International and Abhay Khanna of Suvidha Foundation confirmed this point. Asked if she would be meeting the railways minister to alert him about the problems, Philip said she had no such plan. “We have submitted the report to the ministry of urban development,” she said. The railways spokesman has suggested that the bio-digesters being installed in trains are different--or have superior performance efficiency--compared to those used in land-based units. If this is to be believed, he has raised some serious questions about the performance of the land-based bio-digesters being installed across the country under the government’s Swachh Bharat mission.


Railways ministry: “Total number of bio-toilets installed till 31 October is 97,761 and not only “as 93,537 bio-digesters” as reported by the news. Indian Railways have done extensive experiments along with DRDE GWL to ensure that the discharge is free from pathogens.”

Srinand Jha: The figure of 93,537 bio-toilets until September 30, 2017 is taken from the railways’ response (shown below) on November 2, 2017 to an RTI question. If the railways spokesman is providing a figure upgraded to October 2017, it would clearly be different from the one used in the article.


Railways ministry: “It is not correct to say that bio-toilets in coaches are ineffective or ill-maintained. The waste water discharged from the bio-toilets is tested periodically for specific parameters in order to ensure that the discharged water meets the required norms.

Out of these, 4 tests are carried out in the laboratory of Railways and for balance 2 tests samples are sent to Government approved laboratories. The performance is monitored regularly at various levels.

In fact, a study (copy attached) carried out in 2016 by Council on Energy, Environment and Water (CEEW), a renowned body to conduct high-quality interdisciplinary and cross-issue research on energy, environment and water, has appreciated the various steps taken by Railways to improve its waste management practices including those on moving trains.”

Srinand Jha: Bio-toilets have not passed the performance tests, as is revealed by the agenda papers of the review meeting held by the Railway Board on October 26 (shown below). The CEEW website (https://www.ceew.in) does not contain any study on any report on bio-toilets. The report attached by the Railways Ministry spokesman--titled ‘Waste Management of the Indian Railways’--has, in a passing reference, complimented the railways for its initiative to install DRDO bio-toilets, controlled discharge type toilets and vacuum toilets. This cannot be taken as a certification of efficiency. The Railways have not produced any data in support of any kind of certification by a third party.


Railways ministry: “The reply from Professor Ligy refuting the contention in the news item is as under: ‘DRDO has developed Bio digesters for the treatment of human waste. Such units are being used in large numbers in India for treating human waste. As a part of a research based Industrial project, we have evaluated the performances of bio-digesters based on DRDO technology installed in four southern states of India. For the evaluation, we have selected 15 field installed units and 6 units installed at IIT Madras campus. The study was carried out for two years. The bio-digesters installed at IIT Madras campus were operated under controlled conditions. The operating conditions were varied to find out the performance under different conditions.

The project formulation was done in consultation with Central Public Health and Environmental Engineering organization (CPHEEO), Ministry of Urban Development. The project has an advisory board comprising of 1. Dr. S. Devotta, Earlier Director of National Environmental Engineering Research Institute (NEERI), Nagpur, 2) Prof. Absar Kazmi, Department of Civil Engineering, IIT Roorkee, 3) Mr. Arun Dobhal, Water and Sanitation expert, Unicef (previously) and (presently) World Bank advisor and Mr. Rohit Kakkar, Deputy Advisor CPHEEO. The committee was evaluating the methodology, results and standard operating procedures frequently. The project was funded by Bill and Melinda Foundation through RTI, USA.

The report was submitted to MoUD on Nov. 10, 2017 and the results were presented in person to CPHEEO officials. The evaluation was not for the toilets fitted on railway coaches. The results of the study showed that the bio digesters are not much superior to conventional septic tanks. We also have done extensive analyses of the Inoculum.

We could see significant amount of Psychrophilic microbes in the Inoculum but not in the digesters which were in operation for some time.

Though Hindustan Times and some other media contacted me about the study report, I declined to talk to them. I requested them to contact the ministry of Urban Development for more information. As I have not talked/discussed with any media persons, using my name in the media is unethical.’”

Srinand Jha: This response validates the finding of the IIT Madras study cited in the IndiaSpend report that “bio-digesters were not much superior to the septic tanks (in performance)”. For reasons best known to her, Philip has chosen to deny that she spoke. During my telephonic conversation with her on November 15, she told me that slush was found to be accumulating in the bio-toilets, as it does in any septic tank. She said that the micro-flora examination of human waste also showed that there was not much variation between what a bio-digester can do and what a septic tank does. In the course of this conversation, she did not specify that she didn’t want to be quoted.


Railways ministry: “It is not true that all the bacteria involved in biodegradation process were brought from Antarctica. Instead bacteria from low temperature areas in India were acclimatized to low temperature and the bacterial species which had compromised activity at low temperature were supplemented (bio-augmentation) with selected group of bacteria isolated from lake sediment samples brought from Antarctica.”

Srinand Jha: The following news reports show that the DRDO technology used in bio-digesters has been marketed in the name of the “Antarctica bacteria”:

Next gen toilets

Trains soon to be equipped with DRDO’s bio-digesters

Bacteria from Antarctica aids the setting up of bio-toilets in India

DRDO Using Bacteria from Antarctica in Bio-toilets

In any case, the IndiaSpend report made it clear that a “compound of bacterium” (Antarctica bacteria mixed with cow dung and soil) is being used in the bio-digesters.


Railways ministry: A comment in the news that DRDO has no patent is also wrong. DRDE has more than a dozen national and foreign patents not only on the basic technology but also on the bio-digester fitted in railway coaches. DRDO patent copy attached.

Srinand Jha: The IndiaSpend report said clearly that the DRDO has no patent on the process of bio-digestion of human waste. It has only a patent on the engineering design of the bio-toilet. This becomes clear on reading the patent certification. The DRDO patent is all about engineering and septic tank design. There is no mention on the use of the Antarctica bacteria to aid the bio-digestion process.


Railways ministry: “MoU was signed with DRDO in March 2010.”

Srinand Jha: The DRDO patent on bio-toilets (see above) was awarded in 2015. This was five years after the organization firmed up a MoU with the Indian Railways for the supply of bio-toilets. In other words, the railways in 2010 committed itself to a technology that required thousands of crores of rupees in the anticipation that the DRDO would eventually get a patent on the bio-digester engineering design.


Railways ministry: “No such meeting was held on the stated date (October 26). Notwithstanding this, considering the importance, regular review meetings to monitor and guide the implementation of bio-toilets are held at various levels.”

Srinand Jha: (Scanned copy of the agenda meeting on the review of bio-toilets shown below). Chaired by additional member, Railway Board, the meeting was attended by officials of the Eastern Railways, Northern Railways, Southern Railways, Western Railways, East Central Railways, North Western Railways and the Research Development and Standards Organization (RDSO). The railways ministry spokesman is apparently not aware of the meeting.

Agenda papers ________________________

Railways ministry: “Mounting and security apparatus of toilet tanks faulty, leading to regular breakage of rubber connector and safety wires: Factually incorrect”

Srinand Jha: The point is quoted from the papers of the agenda meeting October 26. See above.


Railways ministry: “The RTI reply was for the total amount of Rs 22 crore spent by Hubli workshop for supply and fitment of 2152 bio toilets.

The current cost of bio-toilet consists of:

a) Supply of bio-digester tanks

b) Supply of strengthening brackets

c) Supply of bacteria Inoculum

d) Specialised welding of strengthening brackets on coaches

e) Installation & commissioning of bio-tanks beneath the coach”

Srinand Jha: Earlier costs had also included manufacturing expenses and fitment of mechanical peripherals. Costs have climbed, which the ministry spokesman is not denying.


Railways ministry: “The statement given by a single anonymous individual source cannot be taken as correct and representative. With implementation of bio-toilets, there is no direct discharge of human waste which resulted in cleaner tracks at station premises. Due to non spattering of faecal matter underneath coach components, maintenance is better. Indian Railways is committed to provide green tracks by implementing bio toilets.”

Srinand Jha: The quote was used to indicate the serious distrust of the programme’s outcome among various sections of railways officials.


Railways ministry: “IR is planning to provide bio-vacuum hybrid toilets not as a replacement of bio toilets, as alleged, but as a complement to save water by an improved flushing system which may lead to reduction in weight of the bio-digesters also. The vacuum assisted toilet is not a substitute to bio-toilets.

There is no policy U turn. The policy continues to be the same except improving flushing system with use of small quantity of water.”

Srinand Jha: Vacuum toilets will come at an additional cost to the railways. “A contraption such as this, vacuum toilets fitted atop bio-digesters, has not been experimented with by any Railways of the world,” a DRDO scientist told me.


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